Roland's proprietary VariPhrase technology was first introduced in the VP-9000, a sample-playback module that processed audio data using innovative techniques

Roland's proprietary VariPhrase technology was first introduced in the VP-9000, a sample-playback module that processed audio data using innovative techniques (see the May 2001 issue). VariPhrase works by analyzing an audio file for pitch, time, and formant information, and then encoding that information in a proprietary format it can manipulate.

The VariOS is a rackmount DSP host processor that brings VariPhrase to the desktop. As its name indicates, the VariOS is an open system implementation, allowing you to integrate VariPhrase processing with other digital audio software. The VariOS hardware module handles the actual processing, freeing your computer for other audio tasks. The VariOS can also be configured as an analog-modeling synthesizer and comes with software emulations of vintage Roland instruments.

The accompanying V-Producer software allows you to construct 6-track songs directly, to create VariPhrase-processed audio files, and to create Standard MIDI Files (SMFs) to control the VariOS hardware from your digital audio sequencer. V-Producer is your window into the world of sonic wizardry: it allows you to manipulate pitch, time, and formants on a timeline. It also lets you apply synthesizer-like processing on a per-file basis, but you can apply different timeline processing to separate instances of the same audio file at different positions on V-Producer tracks.


Pitch shifting, time stretching, and beat slicing are available in a variety of software products. You probably have no-frills versions integrated into your digital audio sequencer, sample editor, or loop-playing software. The VariPhrase system will do all those things, but its virtuosity lies in applying pitch, time, and formant changes in real time during the playback of a phrase. It allows you to change the timbre, timing, and pitch of individual notes within a melodic phrase in different ways for different repetitions of the phrase. It also integrates beat-slicing and slice-sequencing functions and allows you to change the slicing in real time.

Because all the processing is done in the hardware, the VariOS requires only a fairly modest computer configuration — a relatively low-cost laptop, for example. Although processor requirements are relatively light, a good dose of RAM is recommended for running V-Producer. You can use the VariOS by itself in live performance after you create and save Performances in its 32 MB of built-in flash ROM or on PC memory cards. You can also use VariOS-generated sound files in other audio hardware or software (a sample player, for instance).

The VariOS is a bright red, single-rackspace unit with hands-on controls, a backlit LCD, a headphone output, and a PC Card slot on the front panel (see Fig. 1). Three knobs let you manipulate pitch, time, and formant in real time, and pressing the Volume knob plays a preview of your changes. A Value knob, in combination with the Menu button and two Cursor keys, navigates the pages displayed in the LCD.

In addition to MIDI In and Out ports, the rear panel supplies a USB port for connecting to your computer (see Fig. 2). Analog audio jacks include a pair of ¼-inch inputs with a Level trim knob and a mic/line switch, as well as two Direct outputs and two Main outputs, also on ¼-inch jacks. Optical and coaxial S/PDIF ports provide outputs for digital audio, too.

On my Apple PowerBook G4, installing V-Producer and connecting the VariOS was fast and painless in both OS 9 and OS X. Install the software and any necessary drivers (such as OMS or FreeMIDI under Mac OS 9), plug the VariOS into a USB port with the hardware turned off, power up the hardware, and the VariOS will appear on your desktop much like a hard drive. The one caveat is that you can't read from or write to the device directly, and attempting to do so could cause damage. Even with the clear warning in the manual, that might be a fairly easy mistake to make.

The VariOS and V-Producer will work their magic on audio files in AIFF and WAV format, both of which V-Producer automatically converts to the proprietary VariPhrase format. The VariOS comes with a 250 MB library of VariPhrase-formatted samples. The library leans heavily toward bass, drums, and guitar, but with a smattering of flute, strings, and vocals thrown in. In addition, libraries of VariPhrase-formatted samples in a variety of vocal and instrumental categories are available on Zip disks from Roland for $125 each (see “Phrases on Demand” at for details).

In this review, I'll concentrate on using the V-Producer software to set up the VariOS hardware. With the exception of loading and saving audio and MIDI files to your hard drive, though, you can make all the same settings directly on the VariOS using its front-panel controls and two-line LCD. You can accomplish the real-time phrase processing that's available in V-Producer's 6-track sequencer directly using MIDI, though V-Producer makes some of those processes easier.


The first step in using the VariOS is to load audio files with the V-Producer software. V-Producer can load files in three formats: AIFF, WAV, and VariPhrase (VPW). As I indicated earlier, V-Producer automatically analyzes AIFF and WAV files for pitch, time, and formant information. At the same time, it beat-slices the file and saves a copy to your hard drive in VariPhrase format. Conveniently, you can specify whether the analyzed files are placed in the same location as the originals or in a separate directory.

V-Producer's Load Wave Files window is divided into three panes (see Fig. 3). The top left pane shows all your hard drive directories in a nested tree (Windows-Explorer style). When a directory is selected, any eligible files it contains are displayed in the top right pane. You can play selected files using the button with the speaker icon or, if you check the Auto Play checkbox, have them play automatically when you select them. Clicking the Add button places the file in the Load List (bottom pane). For AIFF and WAV files, the type of pitch and formant analysis as well as the suggested tempo are displayed and can be changed in the Load List. VariPhrase files have their analyses already built in. (In any case, the files can be reanalyzed after they are loaded.)

V-Producer offers three methods for analyzing audio files: Solo, Backing, and Ensemble. Solo is intended for melodic material such as solo voices and lead instruments. Backing is primarily for percussion, and Ensemble is for chordal and ambient material. Solo is the only method that incorporates formant information and therefore the only one that allows you to adjust both formants and pitch without a formant change. The Ensemble and Backing methods produce noticeably better pitch shifting for pitched and unpitched material respectively. The MP3 example EnSoBa illustrates the different analysis methods on solo, chordal, and percussive material.

After you select files to load in V-Producer, click on the Load button to initiate the analysis and transfer the files to the VariOS. Loading a large collection of files can take a while; a fuel-gauge-style display pops up to show the progress. When you save a V-Producer song, the sound-file locations (or optionally the sound files themselves) are saved so that you don't need to go through the file-selection and -analysis process again. The load time remains about the same, however.

Setting sample-playback parameters

Once phrase samples are analyzed and loaded into VariOS memory, you can play them with incoming MIDI or arrange them on tracks in V-Producer's 6-track sequencer. How they respond to MIDI and how they can be manipulated on V-Producer tracks is determined by the VariOS's Sample Edit parameters, which you can set up most conveniently in V-Producer's Sample Edit screen (see Fig. 4). You can also set them up using the VariOS control panel and LCD.

The first step is to decide whether to map the sample across the MIDI keyboard as a phrase, in which case notes correspond to pitches, or as a groove, in which case notes correspond to individual slices — drum hits, for example. In addition to the Keymap mode, two other note-related decisions need to be made: the Key Assign mode (Solo or Poly) and the Play Back mode (Retrigger, Time Sync, or Step). Solo mode (not to be confused with the Solo analysis method I described earlier) allows one note to play at a time and gives later notes priority. In Poly mode, multiple notes can play, which means several pitches (if you choose Phrase keymapping) or slices (with Groove keymapping) can sound at the same time.

The Play Back mode controls retriggering and is only relevant for Phrase keymapping. When set to Retrigger, each new note starts the phrase over from the beginning. When set to Time Sync, legato playing — in which new notes are played before existing ones are released — affects only pitch and does not retrigger the phrase. Staccato playing does retrigger the phrase. When set to Step, each new note plays the next slice of the audio file. That's a best-of-all-worlds solution: your timing controls the groove while note selection controls pitch.

The remaining sample-playback settings control parameters such as fine-tuning, Velocity, amplifier, portamento, pan, and LFO settings. Two settings — Robot and Formant Control — apply only to files analyzed using Solo method. When Robot is turned on, the original pitch information is ignored and MIDI notes set the pitch rather than setting a pitch-shift offset. The result sounds robotic. Formant Control makes the formants follow the keyboard; it's turned on by default and usually results in pitch shifting that sounds more natural.

V-Producing your song

Once you've loaded and set up some samples, you can create a song in V-Producer's Vari Track window by dragging samples from the Sample List or by recording MIDI (see Fig. 5). When recording, incoming MIDI plays the sample selected in the Sample List, using the Keymap mode chosen for that sample. Whether by recording or dragging, you wind up with regions, called Frames, containing MIDI data that plays the target sample. You can drag the Frames to different locations as well as copy them. You can also edit the data in the Frames using the PhraseScope or the GrooveScope, depending on the Keymap mode chosen for the sample.

A graphic view of the audio data being played appears in the top pane of the PhraseScope. Beneath that is piano-roll-style display for editing MIDI note positions and lengths. Located at the bottom is a graphic editor for pitch bend, time stretch, formant shift, level (called dynamics), and Velocity; you make edits there by selecting a region and dragging vertically. Three curves are provided for controlling the shape of the change, and you can combine those with different region selections to produce virtually any desired shape.

When you create a Frame by dragging a sample from the Sample list, V-Producer creates a legato sequence of notes at the root pitch, with note divisions corresponding to the sample slices. Because the notes are legato, the Frame will play the full sample rather than retriggering it for each note. The note-editing scheme is both intelligent and flexible. You can resize a note from either end, and the adjoining note will be automatically resized to preserve the legato. You can move a note up or down to transpose the pitch of that section of the sample. You can create new notes with a pencil tool, and they will add harmony or steal the voice, depending on the Key Assign mode. The same features apply for recorded Frames except that, as you would expect, the notes are only legato if played that way.

The GrooveScope has two panes. One shows a graphic of each slice at the position where it will be played; the other is a display that's exactly the same as in the PhraseScope. You can move slices vertically (changing which slice plays) or horizontally (changing when the slice plays), and you can create and delete slices at will. If the sample's Key Assign mode is Poly, you can stack several slices vertically. You can turn quantization off or set its grid from one bar to a 64th-note triplet, and slices can be quantized after the fact with 0 to 100 percent accuracy. There's even a Randomize feature for shuffling any selection of slices.

Manipulating grooves and phrases is extremely fast and intuitive in V-Producer, whether you played them or dragged them into place. The 6-track limitation is a bit restrictive, but considering all the real-time processing that the VariOS hardware has to do, it's not unreasonable. Careful planning will allow you to get around that limit by bouncing tracks to your digital audio sequencer. V-Producer makes that process easy by letting you simultaneously bounce its six tracks to separate audio files.

V-Producer includes a 6-channel mixer with send buses for built-in chorus, reverb, and a multi-effects processor with 40 effects based on various combinations of EQ, compression, distortion, and delay. Each channel has sends to all effects; the multi-effects processor has sends to the chorus and reverb; and the chorus has a send to the reverb. Unfortunately, mixer automation is not possible in V-Producer, so you'll have to bounce the audio or control the VariOS from other software to get that feature.


Under the hood, the VariOS is a high-powered synthesis engine, and VariPhrase processing is only one of its tricks. By loading other software front ends, you can turn the VariOS into a synthesizer of virtually any description, and Roland clearly intends to take advantage of that possibility. To that end, the company has released two examples you can download at no cost from its Web site.

VariOS 303 starts with an exact emulation of Roland's TB-303 Bass Line synth, complete with the same sounds and 16-step pattern sequencer (see Fig. 6). From there it adds a slider screen for easier step-sequence programming and five digital multi-effects — compressor, distortion, equalizer, chorus, and feedback-delay — which work in series.

VariOS-8 is a virtual combination of the Roland Juno and Jupiter series of polysynths (see Fig. 7). It follows the typical analog model, offering a couple of multiple-waveform oscillators, lowpass and highpass filters, and an LFO and envelopes for modulation. From there, it adds the intermodulation between the oscillators and three effects: chorus, reverb, and a multi-effects processor with ring modulator, EQ, pitch shifter, phaser, and delay line, all connected in series. The oscillators and filters are modeled after those in the original synths, and the sound is both authentic and tasty.

You can install the add-on synths in the VariOS's flash ROM or separately on plug-in memory cards. When they are in ROM, you select the VariOS personality when you power up, but you can switch personalities by first quitting the software and then power-cycling the VariOS. The two synths are nice additions, and they definitely whet your appetite to see what Roland has in mind next.


Although V-Producer is specifically designed for the kinds of editing useful for VariPhrase processing, you can use the VariOS as a standalone sound generator driven by a MIDI controller or other MIDI software — your digital audio sequencer, for example. The MIDI implementation is extensive and provides support for all the standard MIDI controllers. If you want to really get into it, you can address every VariOS parameter using SysEx messages.

The VariOS can play as many as six different phrases using the first six MIDI channels. You can also assign a MIDI channel (the default is 16) for controlling global parameters. The phrase for each channel is selected using a MIDI Program Change. Once samples are loaded into the VariOS, you can do the rest of the setup on its control panel, but if you're using your sequencing software, it's easier to run V-Producer simultaneously. V-Producer has windows for assigning MIDI controllers to each of the PhraseScope controllers as well as for setting up MIDI Pitch Bend, Mod Wheel, and After-touch. Once you've set up the VariOS, you can use your sequencer's automation features just as you would the PhraseScope or GrooveScope. You can save songs, and hence setups, on PC Cards or in the VariOS's user memory, in which case you won't need V-Producer to access those setups and their samples.

Another way to work with MIDI, and a very convenient way to get a feeling for how to control the VariOS, is to import SMFs of V-Producer songs. V-Producer exports 6-track SMFs containing all the note and controller information you've created in the PhraseScope or GrooveScope.

Because the VariOS has two stereo audio output buses as well as coaxial and optical digital outs, you have several options for piping VariOS audio back into your digital audio environment. For songs created in V-Producer, you have the additional option of rendering each track or the final mix as WAV files.

The combination of V-Producer and the VariOS provides an excellent-sounding, easy-to-use, highly flexible tool for phrase manipulation and beat slicing. Except for loading the VariOS's sample memory, its extensive MIDI implementation makes it fully functional without V-Producer, which means you can haul it to the gig or studio without your computer. The included sample library is a nice starter set, but you'll undoubtedly want to expand from there. The VariOS is not cheap, but the price seems reasonable considering the processing that's going on inside. Doing the same high-quality job using computer software is not much cheaper and not nearly as convenient.

Minimum System Requirements

Roland VariOS
G3/233 MHz; 192 MB RAM; Mac OS 9.0.4 (OS X compatible); USB portPC: Pentium/500 MHz; 128 MB RAM; Windows 98/2000/ME/XP; USB port

VariOS Specifications

Sound EngineVariPhrase sample playback; analog-synthesis modelingPolyphony(14) notesMultitimbral Parts6Analog Audio Inputs(2) balanced ¼" TRSAnalog Audio Outputs(2) balanced ¼" TRS main; (2) balanced ¼" TRS direct; (1) ¼" stereo headphoneDigital Audio Outputsoptical S/PDIF, coaxial S/PDIFOther ConnectorsMIDI In, Out; USB; IEC ACSampling Frequency44.1 kHzData Format16-bit linearA/D/A Conversion24-bitInternal Processing32-bit (floating point) sound generation; 24-bit (fixed point) effectsSample RAM46 MBFlash RAM32 MBEffectschorus; reverb (9 presets); multi-effects (40 presets)Nominal Input Levelline -18 dBu; mic -43 dBuNominal Output Levelmain +4 dBu; direct +4 dBuDisplay16-character × 2-line backlit LCDDimensions1U × 8.75" (D)Weight4.25 lb.


VariOS (Mac/Win)
DSP engine


PROS: Easy to set up and learn. Integrates easily with MIDI devices and software. Excellent sound quality.

CONS: Can't load samples directly without accompanying software. No mixer or effects automation.


Roland Corporation U.S.
tel. (323) 890-3700